Copying machines



Nov. 5, 1968 w. LIMBERGER COPYING MACHINES Original Filed July 12, 1960 FIG. I

WALTER Lmaenes 1 N VEN TOR.

Attorney United States Patent 4 Claims. -61. 95-89) ABSTRACT OF THE DISCLOSURE A copying apparatus in which the master sheet is led in superimposed relationship with a negative layer and a positive layer inwardly through a single opening in the wall of the machine housing and is then carried around the exposure drum by a powered transport belt prior to separation of the master sheet (and its divergence to an opening in the housing) from the negative and POSI- tive layers. The negative and positive layers are passed between exclusive upper and lower guide members, the former being constituted by the convex bottom of a liquid supply reservoir, while the latter is an upwardly concave trough. At the outlet side the layers are passed between a pair of squeezing rollers.

This application is a division of application Ser. No. 42,312, filed July 12, 1960 (now abandoned).

The present invention concerns producing photocopies by the so-called diffusion process.

The making of copies according to the diffusion method utilizes a negative layer and a positive layer disposed on a carrier, and a bath of a developer fluid through which the positive and negative layers are passed.

A prior method of preparing copies utilizes a photographic negative layer which contains a developer substance and, after exposure, is subjected to heat treatment in contact with a positive layer.

For example, in the use of a developer-fluid bath, it is common procedure to arrange positive and negative layers on the common carrier one above the other in such manner that the positive layer is applied as a first layer, adjacent to the carrier, the negative layer is disposed on this positive layer and the developer fluid acts directly on the negative layer carrying a latent image of an original to which it was photographically exposed.

In this known method, the negative layer must be removed by washing oif with warm water so that an additional operation is necessary which, owing to the washing device required, is also comparatively expensive. Treatment by washing presupposes a certain amount of experience.

This known method has not become popular because of its disadvantages. Normally a carrier sheet having a positive layer and a carrier sheet having an exposed negative layer are passed through a developer fluid and then through a pair of squeezing and conveyor rollers. For the purpose of directly wetting the layers with the developer fluid the layer carriers are brought into the developer fluid through separate introduction passages in a copying apparatus. Within the fluid the development of the negative takes place from the positive side and then there occurs the diffusion into the positive. For the individual layer carriers there can be provided guide paths which pass through the entire bath and are separated by a guide surface. The layer carriers, even after being separately introduced into the fluid, can be pushed together on a guide surface leading through the remaining part of the bath to a pair of squeezing and conveyor rollers.

Patented Nov. 5, 1968 The use of two separate layer carriers is a disadvantage in many respects. Both layer carriers must be suitably aligned with each other first before introduction into the developer bath and must be uniformly introduced, which requires a certain amount of skill. In addition, the lightsensitive negative carriers must be handled as rapidly as possible. This applies, moreover, also when the negative layer carrier is inserted, together with the original to be copied, into an exposure device.

Owing to the use of a separate sheet for the negative layer, it is necessary to use a layer carrier which satisfies certain minimum requirements for the purpose of ensuring a certain degree of rigidity so that it can be arranged without creases over the original, and which is then always discarded after the preparation of a positive, with the result that costs for material are comparatively high.

These disadvantages also occur in the conventional copying procedure in which the development and diffusion are initiated by heating. In this method two sheets are used, one carrying a positive layer and the other a negative layer.

The known two-sheet method in the operation of automatic or semi-automatic copying machines has particular disadvantages. In these cases stacking devices must be provided for the positive layer carriers, separate devices for fitting the negative layer carrier and the positive layer carrier over each other, and also separating devices for the positive and negative layer carriers. The apparatus is large, occupies a great deal of space and is comparatively expensive. Special measures also have to be taken to screen the negative layer from the incidence of light.

Even in the case of a simple combination appliance With an exposure and development device, manipulation with separate positive and negative layer carriers is complicated, since first the negative layer carrier with the original must be removed from the exposure device, then a positive layer carrier must be taken up and fittted over the negative layer carrier, after which this group must be introduced into the developing device with the insertion of the individual layer carriers into separate slots.

An object of the invention is to provide a new method which avoids the disadvantages of the known method.

A further object of the invention is to provide an apparatus for carrying out the diffusion development which surmounts the disadvantages of known methods and renders possible the carrying out of the diffusion treatment as a one-sheet process.

According to the present invention I provide a method of preparing copies by a dilfusion process with the use of a negative layer and a positive layer arranged between two layer carriers in a single composite or unitary sheet which is passed, after exposure, through a developing device and, after development, is split to separate the two layer carriers. A diffusion development may be effected in a bath with developer fluid, the fluid being admitted through one or both layer carriers. However, it is also possible to heat the sheet, whereby materials arranged between the layers give off water of crystallization and the development and diffusion are effected.

Thus, my invention utilizes a-material for preparing copies by the diffusion process wherein negative and positive layers, each mounted on a layer carrier, are combined in one sheet. The positive layer and the negative layer may be arranged in indirect or direct contact with each other and detachably secured together, the carriers being located on the outside of the layer material. A translucent separating layer may be provided between the positive and negative layers for the mechanical separation and simultaneous mechanical connection of the layers. The translucent separating layer, whose light transmissivity enables the making of photocopies by the reflex process,

may contain a substance which is adapted to give off water of crystallization such as, for example, polyvinyl alcohol. Preferably the separating layer contains an adhesive.

The separating layer may be designed in such a manner, or so adjusted with respect to its solubility, that a developer impregnation or a diffusion of activating liquid into the positive layer may at first be prevented and take place only after full development of the negative.

The method according to the present invention may be practiced with the aid of an apparatus having a single guide surface, preferably formed by the base of a container. This makes the construction of the apparatus much simpler and cheaper than heretofore and, if desired, the usual pair of squeezing and conveyor rollers at the end of this guide surface behind the liquid bath can be omitted since the layers, if the separating layer has suitable dimensions, are evenly juxtaposed for a sufiiciently long time.

The invention will now be described further, by way of example, with reference to the accompanying drawing in which:

FIG. 1 is a partial section through a material usable in conjunction with the invention, shown on a greatly enlarged scale;

FIG. 2 is a diagrammatic side view of an apparatus for practicing the method according to the invention;

FIG. 3 is a front view of the apparatus shown in FIG. 2, drawn to a different scale; and

FIG. 4 is an embodiment of an apparatus differing from that of FIG. 2.

The material shown in FIG. 1 consists of a thin flexible carrier 1 which is provided with a comparatively thin positive layer 2. In the embodiment shown, a separating layer 3 is provided in this positive layer; this separating layer exists only in a preferred mode of realization and is not absolutely necessary. On the side of the separating layer 3 remote from the positive layer there is provided a negative layer 4 which is adapted to be drawn off dry. The side of the negative layer 4 remote from the separating layer 3 is provided with a preferably thin, flexible first carrier layer 5 which is preferably of porous absorbent material.

The purpose of the separating layer 3 is to keep the layers 2 and 4 together and, after being thoroughly wetted, to loosen them so that the positive layer 2 can be drawn off; thus the separating layer holds the layers together but is wettable for releasing the layers from one another. The permeable layer carrier 5 is designed to allow developer fluid to penetrate comparatively quickly to the negative layer 4 and to develop this layer. The second layer carrier 1 of the positive layer can be omitted in some instances.

An example is given hereinafter for components of the separating layer which are suitable. This sample relates to a preferred but not exclusive embodiment and other separating layers of different compositions can be utilized.

The separating layer preferably contains the following ingredients:

In the preparation of a copy, the original is laid on the layer carrier 1 in such manner that the illustration or message side faces the layer carrier.

The negative is exposed by the reflex process, the light incidence being effected from below as viewed in FIG. 1.

If the separating layer 3 (which, for example, may consist of a film) does not produce completely automatic detachment of the layers, it is advisable to take steps, preferably on the edge of the material located forwardly in the apparatus, for facilitating mechanical separation. In the embodiment shown this is effected by recessing an edge strip 6. Separation may, however, also be effected, for example, by offsetting the layer 2 and the carrier 1 rela- 4 .1 tively to the layer 4 and the carrier 5, or only one or the other layer carrier relatively to the remainder of the stack.

The embodiment illustrated has the additional advantage of protecting the negative layer against incident light and also, in the event of comparatively long storage, against absorption of moisture.

In FIG. 2 there is shown an apparatus having a casing 7 with an insertion slot 8 on one operating side for the original and the copying material, and a lower delivery slot 9 for the original. Between these slots there is disposed a shelf-like extension 10 outside a delivery slot 11 for the copying material which may be ejected either in its cohesive state or after detachment of the negative layer from the positive layer.

In front of the rear wall of the casing there is disposed, in the upper part of the apparatus, a conventional exposure device 12 with an exposure cylinder 13 and several pressure bands 17 guided over rollers 14, 15, 16 and tensioned by a resilient support 18 for the shaft of the roller 15. The cylinder 13 simultaneously serves to reverse the direction of motion of the original and the copying material and to guide them back to the front of the apparatus. Therefore the cylinder 13 has a comparatively large diameter.

The cylinder 13 is provided, preferably, with shutters 19 which may be adjustable and by which the actual exposure can be limited to a comparatively narrow strip. There is also at least one light source 20 in the cylinder for transilluminating a composite sheet as described with reference to FIG. 1.

Between the insertion slot 8 and the inlet into the exposure device on the roller 14 there is provided a feed table 21 which enables the preliminary storing of a stack consisting of a sheet of copying material and the original.

At the outlet of the exposure device 12 the sheet of copying material and the original are taken over by at guide surface 22. Mounted next to this guide surface, as a separating device, are a pair of separating rollers 23, 24 which rotate in known manner in the same direction and have a gap between them conforming to the size of the original. This means that the cap is equal to or somewhat larger than the thickness of the original but narrower than the thickness of the copying material. The upper separating roller 23 raises the sheet of copying material and conveys it into a developing device 25, while the original runs over the guide surface as far as the delivery shelf 10 and can remain in the apparatus, being accessible from the shelf. A step 26 in the guide surface 22 ensures that subsequent originals can be added to those already disposed on the horizontal receiving surface 27.

The developing device has simply a trough-like guide surface 28 over which there is provided a storage container 29, holding the developer fluid, for covering the liquid bath. For directing the sheet of material onto the guide surface 28 there is used a guide surface 39 overhanging the end of the guide surface 28 and the separating roller 23. The level of the developer fluid is indicated by the reference numeral 40. Between the storage container 29 and the fluid receptacle formed by the trough-like surface 28, an apparatus 41 is provided which regulates the level of fluid in the receptacle. The container is otherwise completely closed; only at the top does it have a filling socket which can be tightly sealed and is accessible from one side of the apparatus. The container 29 can be removably arranged. In this case the aperture 41 may be closed by means of valves (not shown). At the end of the guide surface 28 a pair of squeezing and conveyor rollers 30, 31 are provided. The roller 31 should run tangentially to the guide surface in a recess formed therein. The roller 30 is located at a very small distance from the roller 31, this distance being smaller however than the thickness of the copying material.

FIG. 3 shows a unit 32 provided on one side of the assembly just described, which contains the driving and switch devices therefor. As seen in FIG. 2, the drive of all the rotating parts is effected by way of a central driving disk 33 from which transmissions 34, 35, 36, 37, shown in broken lines, pass to the individual rollers.

According to FIG. 3, the unit 32 is associated with a driving motor 42 which drives the central driving disk 33 shown in FIG. 2. Moreover, the unit 32 is provided with connections 43 to the main supply for feeding the exposure light source and an exposure time clock. Between the unit 32 and the interior of the apparatus shown in FIG. 2 there is preferably provided a partition 44 in which the shafts of all the rotating parts are journaled for rotation in the direction indicated by arrows. The shaft ends on the other side of the rotating parts can be journaled in the wall 44' of the casing. In the case of a narrow apparatus, the unit 32 can be provided at least partly in the compartment that houses the storage container 29.

A smaller construction is obtained if the arrangement of the components is turned upside doWn, i.e. if the original and the copying material are introduced from below. In this case the trough of the developer container is located near the exposure cylinder so that the assembly can be much shallower. This last construction has the special advantage that a very curved guide surface for the developer bath can be provided so that a long developer bath path can be obtained without additional space requirements.

In FIG. 4, which shows such a construction, corresponding parts are designated by the same reference numerals. A delivery slot 38 for the original is provided at the top of the apparatus. The driving means are not shown in detail. Their construction will be apparent from a comparison with the embodiment shown in FIGS. 2 and 3. It should be pointed out that the pressure device in front of the delivery slot 11 shown in FIG. 4 consists merely of a squeezing and conveyor roller 45 which is spacedly disposed above the guide surface 46. The clearance is smaller than the thickness of the material conveyed through the trough 47 of the developer device. The fluid level in this trough is indicated by 48. The trough is covered at the top by a storage container 49. This storage container is arranged and constructed according to the storage container 29.

I claim:

1. A copy apparatus for producing a copy of a master sheet upon an externally applied positive layer by forming a latent image in an externally supplied negative layer and effecting diffusion transfer between said negative layer and said positive layer, said apparatus comprising:

a housing;

developing means in said housing formed with an upwardly concave trough receiving a liquid developer and constituted substantially of an exclusive lower guide member for said positive and negative layers, and a supply container for delivering said liquid to said trough and having a downwardly convex underside forming an exclusive upper guide member for said positive and negative layers, said guide members defining between them a single inlet for admitting said positive and negative layers between said members and into the liquid in said trough, said members further defining between them an outlet for said positive and negative layers remote from said inlet;

powered squeezing-roller means adjacent said outlet for compressing the positive and negative layers against one another upon their passage between said members and through said liquid and upon their emergence from said developing means;

a single first opening formed in said housing for introducing said master sheet and said negative and positive layers thereto in superimposed relation, and second and third openings formed in said housing for discharging said master sheet and said positive and negative layers therefrom, said third opening being aligned with said outlet, said lower guide member projecting beyond said upper guide member to said third opening from said outlet;

exposure means between said first opening and said inlet and adapted to form said latent image in said negative layer;

a guide plate leading from said first opening to said exposure means;

powered transport means for conducting said master sheet, said negative layer and said positive layer in superimposed relation through said exposure means; and

separating means between said exposure means and said inlet for diverting said master sheet to said second opening and said layers to said inlet.

2. An apparatus as defined in claim 1 wherein said squeezing-roller means comprises a roller spaced from the portion of said lower guide member projecting beyond said upper guide member by a distance less than the combined thicknesses of said layers.

3. An apparatus as defined in claim 1 wherein said separating means includes another guide plate leading from said second opening substantially to the region of said exposure means and powered roller means co-operating with said guide plate for deflecting said layers and said sheet along divergent paths.

4. An apparatus as defined in claim 3 wherein said housing is generally prismatic and said first and third openings are formed in a common wall of said housing.

References Cited UNITED STATES PATENTS 2,692,830 10/1954 Land 9629 2,732,778 1/1956 Limberger 89 2,903,954 9/1959 Schwienbacher 95-89 2,925,025 2/1960 Conner 95-89 3,088,824 5/1963 Jacobs 9589 NORTON ANSHER, Primary Examiner.

FRED L. BRAUN, Assistant Examiner. 

